1 Field of the Invention
This invention relates to a cabinet and product display shelf therefor and more specifically to a display shelf for products of different vertical heights that is adapted to be quickly attached or detached on the inside surface of a transparent panel of the cabinet through which products are viewed by customers.
2. Description of the Related Art
Product point-of-sale display cabinets such as coolers and freezers contain a plurality of conventional shelf elements in the interior space of the cooler on which products are displayed. The cooler is provided with an openable access door having a large transparent panel through which the products on the shelves can be viewed. There exists an unused dead space between the inside surface of the door panel and the conventional shelf elements of the cooler. The dead space extends from side-to-side and top-to-bottom of the transparent door panel. While it has been desired to use this dead space for additional product display, existing shelves have not been entirely satisfactory for additional product display because of problems relating to retention, capacity and access to products on the shelf.
When the door is swung open, inertial forces are generated which can cause products on the display shelf to be dislodged. Therefore, door mounted display shelves must have some means for retaining products on the display shelf to prevent them from being dislodged as the door swings open. The retaining means most often used is a vertical retaining wall along the front edge of the shelf. A vertical retaining wall must satisfy three basic requirements that have in the past been irreconcilable. The retainer wall must be high enough to prevent the product from tipping over the top edge of the retainer (retentiveness); high enough to give the shelf adequate capacity to hold small size products (capacity); and low enough to permit convenient access of a hand for quick removal of the product (access).
A vertical retaining wall can easily meet retentiveness, capacity and access requirements when the products are all of a uniformly tall size and extend above the top of the retainer wall. However, when the products are all vertically short and small, or both large and small products are to be placed on the same shelf, problems arise with regard to retentiveness, capacity and access for removal of products.
In order to maximize the capacity of the shelf to hold small items such as candy bars, it is desirable to make the vertical retaining wall as high as possible. However, when the upper edge of the retaining wall is above the vertical height of a single product, access becomes more restricted and retrieval of the product starts to become more awkward and difficult. The higher the retainer wall relative to the vertical height of a single product, the more restricted the access becomes. If, for example, the candy bars are stacked horizontally four layers high, the top level of bars is easily accessed for removal but removal of the bars in the second, third or fourth levels becomes successively more difficult. In theory, it would be possible to stack products such as candy bars on end so that they project above the retainer wall, but this is not practical. As soon as some bars are removed, the remaining bars tend to fall down sideways, coming to rest on the shelf below the retainer wall where they are difficult to reach.
Ease of product removal is very important because it significantly affects operating costs. When the customer has trouble extending his fingers down over the top edge of the retainer wall for access to the candy bar, more time is taken in the removal process. The customer will hold the door open as long as necessary to remove the candy bar. Increase of door open time drastically increases the operating cost of the refrigerated cooler because a longer period of open time allows more refrigerated air to leave the cooler. Increasing the time the door is held open by only 15 or 20 seconds multiplied by thousands of openings during a typical week of operation results in an incredible increase in total operating cost of the refrigerated cooler. Open time not only increases operating costs but it also shortens the operating life of the cooler's refrigeration system.
The requirements for retentiveness, access and capacity have been even more difficult to meet when it is desired to place products of differing vertical dimensions on the same display shelf. With a tall product the retainer wall must be high to prevent the product from being dislodged when the door is abruptly pulled open. However, this high retainer wall can totally prevent access to a vertically short product placed on the same shelf. This problem has never been satisfactorily solved.
Therefore, the height of the retainer wall has, of necessity, always been a compromise in which retentiveness, shelf carrying capacity and access to products are all sacrificed to a significant degree. Historically, the only known way to avoid compromise of the retentiveness, access and capacity requirements is to provide a plurality of different shelves each with differing heights of retainer walls tailored to the size of the product. Unfortunately, tailored shelves also have unsatisfactory consequences. With tailored shelves, the merchant must purchase several different sizes of shelves thereby increasing his initial costs. Only some of these shelves are in use at any one time. The unused shelves must be stored and are subject to damage during handling and storage. Further, if a different size product is to be placed in the cooler, one size shelf must be removed and another installed in its place and this increases stocking time and labor costs.
With the teachings of the prior art it has not been possible to design a single, universal display shelf that will permit retentiveness, capacity and access requirements to be maximized for both tall and short products.